According to the Midol website, depending on the product, the main ingredients in Midol are either acetaminophen or a nonsteroidal anti-inflammatory drug, such as ibuprofen or naproxen sodium. Each of the formulations available as of October 2014 contains additional ingredients, including caffeine, antihistamines, diuretics and sleep aids.
As of October 2014, the Midol website lists five unique formulations meant to alleviate cramps and other symptoms that accompany the menstrual period. Midol Complete, available in caplets or gelcaps, contains acetaminophen for pain relief as well as caffeine to alleviate bloating and fatigue. It also includes the antihistamine pyrilamine maleate to combat swelling related to water retention.
Midol Extended Relief contains 220-milligram naproxen-sodium tablets to provide relief from cramps, backache and headache for up to 12 hours, according to the Midol website. Midol Teen Formula contains acetaminophen for pain alleviation and the diuretic pamabrom to combat bloating.
The website describes Midol Liquid Gels as containing 200 milligrams of ibuprofen to provide relief of cramps, backache, headache and muscle aches. Midol PM coated caplets combine acetaminophen for pain relief with a non-habit-forming sleep aid called diphenhydramine citrate. Meant to be taken at night, this formulation relieves cramps, backache and headache while promoting sleep.